11. MINIMUM/MAXIMUM
WATER CONTENT IN THE
SYSTEM
11.1. MINIMUM/MAXIMUM CONTENT OF
SYSTEM WATER,
FOR UNITS WITHOUT
HYDRONIC KIT
11.2. RECOMMENDED MAXIMUM WA-
TER CONTENT
Table 11.2.1indicates maximum water
content in litres of hydraulic plant, com-
patible with expansion vessel capacity
supplied as standard (FOR VERSIONS
WITH PUMP). The values shown in the
table refer to three maximum and
minimum water temperature conditions.
If the effective water content of the
hydraulic system is greater than that
shown in the table, whist active, an ad-
ditional expansion vessel is required. Use
usual criteria, referring to volume of ad-
ded water, to determine size required.
From tables 11.2.2 it is possible to obtain
the maximum content values for the
system also for glycoled water functio-
ning conditions.
Values are worked out by multiplyingthe
referred value by the corrective co-
efficient.
11.3. EXPANSION TANK CALIBRATION
The standard pre-load pressure value
of the expansion vessel is 1.5 bar, while
their volume is 25 litres. The maximum
value is 6 bar.
Vessel calibration must be regulated
using the maximum level difference (H)
of the user (see diagram) by using the
following formula.
p (calibration) [bar] = H [m] / 10.2 + 0.3
For example: if level difference (H) is
equal to 20m, the calibration value of
the vessel will be 2.3 bar.
If the calibration value obtained from
thecalculation is less than 1.5 bar (i.e. for
H < 12.25), keep standard calibration.
(1) Minimum water content
(2)
Minimum water content in the case
of process applications or applications
with low load.
∆t di progetto minore di 5°C.
NXW
n° Com-
pressor
(1) l/KW (2) l/KW
0500
3510
0550
0600
448
0650
0700
0750
448
0800
0900
1000
1250
1400 5 4 8
H max
(1)
= 55 m
H = 12.25 m
H
H = 0 m
Ptar = H / 10.2 + 0.3
Ptar = 1.5 bar
Ptar = 1.5 bar
H min
(2)
H
NXW
Hydraulic height
H m30252015
≥ 12.25
Calibration of the expansion vessel bar 3.2 2.8 2.3 1.8 1.5
Water content reference value l
(1)
2.174 2.646 3.118 3590 3852
Water content reference value l
(2)
978 1190 1404 1616 1732
Glycoled
water
Water temp. °C Corrective
co-efficients
Reference
condition
max. min.
10% 40 -2 0,507 (1)
10% 60 -2 0,686 (2)
20% 40 -6 0,434 (1)
20% 60 -6 0,604 (2)
35% 40 -6 0,393 (1)
35% 60 -6 0,555 (2)
Reference operational conditions:
(1) Cooling: Max water temp. = 40 °C, min water temp. = 4 °C.
(2) Heating (heat pump): Max water temp. = 60 °C, min water temp. = 4 °C.
KEY
(1) Check that highest installation does
not exceed a height difference of 55
metres.
(2) Ensure that lowest installation can
withstand global pressure in that position
11.2.1
11.2.2
27
INXWPY. 1004. 4438805_00
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